Originally Posted by Delano
Poly was initially marketed to rec players (and still is) as a durable string for string breakers. I don't think that's a good way to think about poly. You're generally safe playing with nat gut until it breaks because it's a soft string with good resiliency. Poly is the opposite. To me, the "durability" of poly is more of a liability than an asset, because it means it won't break until long after it goes dead (with predictable effects on your arm).
Now that I use a a copoly, low tension, and restring before it goes dead, I haven't had any trouble at all with arm soreness from poly.
I agree with everything here. Well said and great advice. If only every stringer out there knew about this phenomenon, we'd have a lot less wrist and elbow overuse injuries out there.